Multi-wavelength B, V , R, I observations of the optical afterglow of GRB050319 were performed by the 1.05-m telescope at Kiso Observatory and the 1.0-m telescope at Lulin Observatory from 1.31 hours to 9.92 hours after the burst. Our R band lightcurves, combined with other published data, can be described by the smooth broken power-law function, with α1 = −0.84 ±0.02 to α2 = −0.48±0.03, 0.04 days after the GRB. The optical lightcurves are characterized by shallow decays— as was also observed in the X-rays— which may have a similar origin, related to energy injection. However, our observations indicate that there is still a puzzle concerning the chromatic breaks in the R band lightcurve (at 0.04 days) and the X-ray lightcurve (at 0.004 days) that remains to be solved. Subject headings: gamma-ray: burst : afterglow Institute of Astronomy, National Central University, Chung-Li 32054, Taiwan, Republic of China. (Huang email: d919003@astro.ncu.edu.tw) Department of Physics, Saitama University, Shimo-Okubo, Sakura, Saitama, 338-8570, Japan. RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan. Department of Physics, Kyoto University, Kyoto 606-8602, Japan Kiso Observatory, Institute of Astronomy, The University of Tokyo, Mitake-mura, Kiso-gun, Nagano 397-0101, Japan. Department of Physics, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan. Department of Astronomy and Earth Sciences, Tokyo Gakugei University, Koganei, Tokyo 184-8501, Japan. National Astronomical Observatories, Chinese Academy of Sciences, Beijing 100012, China, PR. Department of Physics, Nagoya University, Furo-cho, Chikusa, Nagoya, Aichi 464-8602, Japan.